Apparatus of structured light generation

ABSTRACT

An apparatus of structured light generation is equipped with a light source and a lens unit. The lens unit is installed in a compact housing of the apparatus of structured light generation. Moreover, the lens unit constructed two different optical path lengths within the housing. By the lens unit, light beams from the light source are collimated and converted into linear light beams. The linear light beams are locally overlapped or globally overlapped. Consequently, the light beam from the light source is shaped into a linear structured light or a linearly-overlapped structured light for detection.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of co-pending continuation-in-partapplication Ser. No. 15/071,935, filed on Mar. 16, 2016, which claimspriority of U.S. application Ser. No. 14/595,651, filed January 13,2015, now U.S. Pat. No. 9,322,962, for which priority is claimed under35 U.S.C. §120; and this application claims priority of Application Nos.1036137857, 103219360, 103137850 filed in Taiwan on Oct. 31, 2014 under35 U.S.C. §119; the entire contents of all of which are herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention relates to an apparatus of structured lightgeneration, and more particularly to a slim-type apparatus of structuredlight generation.

BACKGROUND OF THE INVENTION

In recent years, the elements, devices, modules, apparatuses orinstruments for detecting interactive gestures, postures or 3D scanningtrajectories have been increasingly developed. For example, an infrared(IR) structured light can be employed to achieve the above detectingfunction. In the meantime, a planar scanning structured light is alsopreferred to employ in recognizing the interactive actions or theimportant indicating objects. In practical implementation, a collimatingbeam is required in the generation mechanism to make such a structuredlight. As a result, a collimated infrared light is necessary to achievethis function. However, since the current light source module with thefunction of generating the collimated light has bulky volume, this lightsource module cannot meet the requirements of the modern slim typemobile phone, wearable devices, and so on.

On the other hand, the current light source module is usually equippedwith a dust-proof lens at a side of a housing thereof. The dust-prooflens can increase the resistance of the light source to the harshenvironment and enhance the stability of the light source. The materialof the dust-proof lens is typically a glass plate. In some situations,the dust-proof lens may be omitted or integrated into other part.However, if the dust-proof lens is omitted, the optical path length orthe working distance is possibly changed. The change of the optical pathlength or the working distance may adversely affect the operation of thelight source module, i.e., the effective back focal length is changedand the collimating property is varied. Therefore, it is important todevelop a lens which is capable to work well both with/or without thedust-proof lens and install it in a compact-size and user-friendlyapparatus of structured light generation in a mobile phone so as toextract 3D information or achieve the 3D gesture or scanning function.

SUMMARY OF THE INVENTION

An object of the present invention provides an apparatus of structuredlight generation for achieving a 3D sensing function. The apparatus ofstructured light generation uses a lens unit to construct at least twooptical path lengths. Consequently, the flexibility of using theapparatus of structured light generation is enhanced.

Another object of the present invention provides an apparatus ofstructured light generation comprising a lens unit with a lens element.The lens element has a first surface for collimating a visible orinvisible laser beam and a second surface for shaping the collimatedlaser beam as a linear light beam. Consequently, the parallel linearlight beam is generated.

In accordance with an aspect of the present invention, an apparatus ofstructured light generation is provided. The apparatus of structuredlight generation includes a light source, a lens unit and a housing. Thelight source emits a light beam. The lens unit converts the light beaminto a linear light beam. The lens unit includes a lens element with afirst surface and a second surface. The first surface and the secondsurface are opposed to each other. The first surface faces the lightsource. In addition, the first surface has a radius larger than 0.189 mmor has a diffracting function. The housing accommodates the light sourceand the lens unit. Within the housing, the lens unit constructs a firstoptical path length and a second optical path length for the light beam.The first optical path length and the second optical path length aredifferent.

In an embodiment, the first surface of the lens element is an asphericsurface or a free-form surface, and a lenticular lens array structure isformed on the second surface of the lens element. Alternatively, alenticular lens array structure is formed on the first surface of thelens element, and the second surface of the lens element is an asphericsurface or a free-form surface.

In an embodiment, the lens unit further includes a dust-proof platebetween the light source and the lens element, and the lens element andthe dust-proof plate are made of an identical material or differentmaterials. In this circumstance, the materials can be glass or non-glasstype.

In an embodiment, the lens unit further includes a mixed type opticalstructure. The mixed type optical structure contains a diffractivestructure, a reflective structure and/or a refractive structure. Themixed type optical structure is arranged between the light source andthe lens element.

In an embodiment, the first surface of the lens element has a phasedistribution given by a formula:

${\varphi (r)} = {{dor}\frac{2\pi}{\lambda_{0}}\left( {{{df}\; 0} + {{df}\; 1r^{2}} + {{df}\; 2r^{4}} + {{df}\; 3r^{6}} + {{df}\; 4r^{8}} + \cdots}\; \right)}$

-   where, r²=x² +y²,-   wherein φ(r) is the phase distribution, r is the distance between    any point and a center of the first surface, and x and y are two    coordinates of two axes vertical to an optical axis or a Z axis,    wherein dor=1, df0=0.0, df1=−6.1691×10̂(−1), df2=2.8442×10̂1,    df3=−4.8405×10̂3, df4=2.800×10̂5, df5=4.6892×10̂(−2),    df6=3.1385×10̂(−4), and the lens element with the aspheric surface    has an effective focal length smaller than 1.2 mm.

In an embodiment, the light beam is collimated by the first surface ofthe lens element, and the collimated light beam is converted into thelinear light beam by the second surface of the lens element.

In an embodiment, the lens unit further includes a dust-proof platebetween the light source and the lens element. The lens element and thedust-proof plate are made of an identical material or differentmaterials. The lens element is made of poly(methyl methacrylate),polycarbonate, cyclo-olefin polymer or high density polyethylene, whichis transparent in a corresponding wavelength range.

In an embodiment, the first surface of the lens element has an asphericsurface, a lenticular lens array structure is formed on the secondsurface of the lens element, and a surface profile of the asphericsurface is given by a following formula:

$z = {\frac{{cvr}^{2}}{1 + \sqrt{1 - {{{cv}^{2}\left( {{cc} + 1} \right)}r^{2}}}} + {{as}\; 0} + {{as}\; 1r^{2}} + {{as}\; 2r^{4}} + {{as}\; 3r^{6}} + {{as}\; 4r^{8}} + {{as}\; 5r^{10}} + {{as}\; 6r^{12}} + \ldots}$

wherein z is a Z-axis coordinate of a specified point on the asphericsurface from a vertex, CV is a radius of curvature, CC is a coniccoefficient, as0=as1=0.0, as2=9.6037×10̂1, as3=−4.1955×10̂3,as4=−2.5357×10̂4, as5=−7.2472×10̂1, and as6=−3.0699.

In an embodiment, the first surface of the lens element is a flatsurface with the diffracting function, and the first surface has a phasedistribution given by a formula:

${\varphi (r)} = {{dor}\frac{2\pi}{\lambda_{0}}\left( {{{df}\; 0} + {{df}\; 1r^{2}} + {{df}\; 2r^{4}} + {{df}\; 3r^{6}} + {{df}\; 4r^{8}} + \cdots} \right)}$

-   where, r²=x²+y²,-   wherein φ(r) is the phase distribution, r is the distance between    any point and a center of the first surface, and x and y are two    coordinates of two axes vertical to an optical axis or a Z axis,    wherein dor=1, df0=0.0, df1=−6.1691×10̂(−1), df2=2.8442×10̂1,    df3=−4.8405×10̂3, df4=2.800×10̂5, df5=4.6892×10̂(−2), and    df6=3.1385×10̂(−4).

In an embodiment, a lenticular lens array structure is formed on thefirst surface of the lens element, the second surface of the lenselement has an aspheric surface, and a surface profile of the asphericsurface is given by a following formula:

$z = {\frac{{cvr}^{2}}{1 + \sqrt{1 - {{{cv}^{2}\left( {{cc} + 1} \right)}r^{2}}}} + {{as}\; 0} + {{as}\; 1r^{2}} + {{as}\; 2r^{4}} + {{as}\; 3r^{6}} + {{as}\; 4r^{8}} + {{as}\; 5r^{10}} + {{as}\; 6r^{12}} + \ldots}$

wherein z is a Z-axis coordinate of a specified point on the asphericsurface from a vertex, CV is a radius of curvature, CC is a coniccoefficient, as0=as1=0.0, as2=9.6037×10̂1, as3=−4.1955×10̂3,as4=−2.5357×10̂4, as5=−7.2472×10̂1, and as6=−3.0699.

In an embodiment, the first optical path length or the second opticalpath length comprises one or plural working distances. Moreover, adifference between the plural working distances is smaller than 1.2 mm.

In an embodiment, the light source includes plural light-emitting chips,and the lens element includes plural light-transmissible regions. Afterthe light beam from each of the light-emitting chips passes through thecorresponding light-transmissible region of the lens element, the lightbeam is converted into at least one linear light beam by thecorresponding light-transmissible region. The linear light beamsoutputted from the plural light-transmissible regions are locallyoverlapped, globally overlapped, or not overlapped.

In accordance with another aspect of the present invention, an apparatusof structured light generation is provided. The apparatus of structuredlight generation includes a light source, a lens unit and a housing. Thelight source emits a light beam. The lens unit converts the light beaminto a linear light beam. The housing accommodates the light source andthe lens unit. The housing includes a first side and a second side. Thefirst side and the second side are opposed to each other and open to anoutside of the casing. A distance between the first side and the secondside is not larger than 4 mm. The light source is located near the firstside. The lens unit is located near the second side. Within the housing,the lens unit constructs a first optical path length and a secondoptical path length for the light beam. Moreover, the first optical pathlength and the second optical path length are different.

In an embodiment, the lens unit includes a lens element, and a radius ofa first surface of the lens element is larger than 0.189 mm. The firstsurface faces the light source. The first surface is an aspheric surfaceor has a lenticular lens array structure. The first surface has aneffective focal length smaller than 1.2 mm.

In an embodiment, a second surface of the lens element is an asphericsurface or has a lenticular lens array structure, and the second surfaceof the lens unit is close to the second side of the housing and facesthe outside of the housing.

In an embodiment, the lens unit further includes a dust-proof platebetween the light source and the lens element.

In an embodiment, the lens unit includes a lens element. A first surfaceof the lens element is a flat surface with a diffracting function. Thefirst surface has a phase distribution given by a formula:

${\varphi (r)} = {{dor}\frac{2\pi}{\lambda_{0}}\left( {{{df}\; 0} + {{df}\; 1r^{2}} + {{df}\; 2r^{4}} + {{df}\; 3r^{6}} + {{df}\; 4r^{8}} + \cdots} \right)}$

-   where, r²=x²+y²,-   wherein φ(r) is the phase distribution, r is the distance between    any point and a center of the first surface, and x and y are two    coordinates of two axes vertical to an optical axis or a Z axis,    wherein dor=1, df0=0.0, df1=−6.1691×10̂(−1), df2 =2.8442×10̂1, df3    =−4.8405×10̂3, df4=2.800×10̂5, df5=4.6892×10̂(−2), and    df6=3.1385×10̂(−4).

In an embodiment, the light source includes plural light-emitting chips,and the lens element includes plural light-transmissible regions. Afterthe light beam from each of the light-emitting chips passes through thecorresponding light-transmissible region of the lens element, the lightbeam is converted into at least one linear light beam by thecorresponding light-transmissible region. The linear light beamsoutputted from the plural light-transmissible regions are locallyoverlapped, globally overlapped, or not overlapped.

In an embodiment, the plural light-emitting chips are programmed to beindividually turned on or turned off in identical or different timesegments.

In an embodiment, the light source includes one light-emitting chip, orthe light source includes plural light-emitting chips that aredistributed on a curvy substrate.

The above objects and advantages of the present invention will becomemore readily apparent to those ordinarily skilled in the art afterreviewing the following detailed description and accompanying drawings,in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a first embodimentof the present invention;

FIG. 2 is a schematic cross-sectional side view illustrating a variantexample of the apparatus of structured light generation according to thefirst embodiment of the present invention;

FIG. 3 is a schematic cross-sectional side view illustrating anothervariant example of the apparatus of structured light generationaccording to the first embodiment of the present invention;

FIG. 4 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a secondembodiment of the present invention;

FIG. 5 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a third embodimentof the present invention;

FIG. 6 is a schematic cross-sectional side view illustrating a variantexample of the apparatus of structured light generation according to thethird embodiment of the present invention;

FIG. 7 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a fourthembodiment of the present invention;

FIG. 8 is a schematic perspective view illustrating an apparatus ofstructured light generation according to a fifth embodiment of thepresent invention;

FIG. 9 is a schematic exploded view illustrating the apparatus ofstructured light generation according to the fifth embodiment of thepresent invention;

FIG. 10 is a schematic exploded view illustrating a variant example ofthe apparatus of structured light generation according to the fifthembodiment of the present invention;

FIG. 11 is a schematic exploded view illustrating another variantexample of the apparatus of structured light generation according to thefifth embodiment of the present invention;

FIG. 12 is a schematic perspective view illustrating an apparatus ofstructured light generation according to a sixth embodiment of thepresent invention; and

FIG. 13 is a schematic exploded view illustrating the apparatus ofstructured light generation according to the sixth embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a first embodimentof the present invention. As shown in FIG. 1, the apparatus ofstructured light generation 1 includes a light source 10, a housing 12and a lens unit 14. The housing 12 provides an accommodation space foraccommodating the light source 10 and the lens unit 14. An example ofthe light source 10 includes but is not limited to a laser diode (LD), alight emitting diode (LED), an organic light emitting diode (OLED) or athermal source. Generally, the housing 12 is opaque. The housing 12includes a first side 121, a second side 123 and a fixing structure 122.The first side 121 and the second side 123 are opposed to each other.The fixing structure 122 is disposed within the housing 12. In thisembodiment, the fixing structure 122 is used for fixing the light source10 at the first side 121 and fixing the lens unit 14 at the second side123. It is noted that the functions of the fixing structure 122 are notrestricted. The fixing structure 122 may be a one-piece structure or anassembled structure. Moreover, the fixing structure 122 may be installedwithin the housing 12 or directly integrated with the housing 12.Moreover, the housing 12 is designed to have a compact size, and thusthe apparatus of structured light generation 1 of the present inventionis suitably applied to a camera phone. For example, each of the firstside 121 and the second side 123 has a dimension of 4-6 mm×6 mm, and thedistance between the first side 121 and the second side 123 is about2.5-7 mm, and preferably 4.0 mm Moreover, the shapes of the first side121 and the second side 123 are not restricted to square shapes orcircular shapes.

The light source 10 includes one or plural light-emitting chips 102 anda package structure 101. For example, the light-emitting chip 102 mayemit an infrared laser beam with a wavelength of 830 nm and a diffusionangle of about 20 degrees. In addition, the light-emitting chip 102 ispackaged by the package structure 101. The number of the one or plurallight-emitting chips 102 packaged within the package structure 101 isnot restricted. In an embodiment, plural light-emitting chips 102 arefirstly distributed on different positions of a substrate and thencovered by the package structure 101. For clarification and brevity,only a single light-emitting chip 102 is shown in FIG. 1. An example ofthe package structure 101 includes but is not limited to a CAN packagestructure, a DIP package structure, a QFP package structure or a surfacemount device. Basically, the package structure 101 includes a main body105 and one or plural pins 103. The one or plural pins 103 are protrudedout of the main body 105 or disposed on a surface of the main body 105.As shown in FIG. 1, the pins 103 are protruded out of the housing 12 ina direction vertical to the first side 121. The thickness of the mainbody 105 in the direction vertical to the first side 121 isapproximately not larger than 1 mm. It is noted that the thickness ofthe main body 105 is not restricted. Moreover, the light source 10 maygenerate an emitting pattern of symmetrical circular light spots orasymmetrical elliptic light spots. In other words, the lens unit 14 ofthe present invention can be applied to the light source 10 thatgenerates the symmetric or asymmetric emitting pattern.

In this embodiment, the lens unit 14 includes a lens element, wherein anumerical aperture of the lens element is larger than 0.1 and less than0.5, preferably about 0.2. The lens element includes a first surface 141and a second surface 143. The first surface 141 is a curvy surface witha curvature of radius larger than 0.189 mm. The second surface 143 hasanother optical structure. The first surface 141 faces the light source10 (or the first side 121 of the housing 12), and the second surface 143faces the second side 123 of the housing 12. The distance between thefirst surface 141 of the lens element and the light source 10 is about1.00 mm. The light source 10 may emit a light beam. The lens unit 14constructs a first optical path length for the light beam. Moreover, thefirst surface 141 of the lens element is an aspheric surface or afree-form surface for collimating the light beam from the light source10. Preferably, the radius of the first surface 141 is in the rangebetween 0.18935 and 0.1894 mm. The surface profile of the asphericsurface may be expressed by the Z-axis coordinate of a specified pointon the aspheric surface. The Z axis is in parallel with the opticalaxis. In particular, the surface profile of the aspheric surface may begiven by the following formula:

$z = {\frac{{cvr}^{2}}{1 + \sqrt{1 - {{{cv}^{2}\left( {{cc} + 1} \right)}r^{2}}}} + {{as}\; 0} + {{as}\; 1r^{2}} + {{as}\; 2r^{4}} + {{as}\; 3r^{6}} + {{as}\; 4r^{8}} + {{as}\; 5r^{10}} + {{as}\; 6r^{12}} + \ldots}$

In the above formula, z is the Z-axis coordinate of a specified point onthe aspheric surface from the vertex, CV is the radius of curvature, CCis the conic coefficient, (asn) indicate the aspheric coefficientscorresponding to different order terms of radius, wherein n indicates 0or a positive integer. For example, as0=as1=0.0, as2=9.6037 ×10̂1,as3=−4.1955×10̂3, as4=−2.5357×10̂4, as5=−7.2472×10̂1, and as6=−3.0699. Itis noted that the aspheric coefficients are not limited thereto.Moreover, the effective focal length of the lens element is preferablysmaller than 1.2 mm, and more preferably smaller than 1.0 mm. The lenselement is made of poly(methyl methacrylate) (PMMA) or any otherappropriate transparent material in a corresponding wavelength range.For example, the transparent material is polycarbonate (PC),cyclo-olefin polymer (COP resin) or high density polyethylene (HDPE).

In this embodiment, after the collimated light beam is converted into alinear light beam by the second surface 143 of the lens element, astructured light is outputted from the apparatus of structured lightgeneration 1. It is noted that numerous modifications and alterationsmay be made while retaining the teachings of the invention. FIG. 2 is aschematic cross-sectional side view illustrating a variant example ofthe apparatus of structured light generation according to the firstembodiment of the present invention. As shown in FIG. 2, a lenticularlens array structure is formed on the second surface 143′ of the lenselement, wherein the curvature of the lenticular lens array structure is−64 degrees in the X-axis direction vertical to optical axis.Alternatively, the profiles of the first surface and the second surfaceof the lens element may be exchanged. FIG. 3 is a schematiccross-sectional side view illustrating another variant example of theapparatus of structured light generation according to the firstembodiment of the present invention. As shown in FIG. 3, a lenticularlens array structure is formed on the first surface 141″ of the lenselement, and the second surface 143″ of the lens element is an asphericsurface or a free-form surface. Preferably, the overall thickness of thelens element is not larger than 1.2 mm. Consequently, the thickness ofthe housing in the Z-axis direction or the optical axis direction is notlarger than 4 mm. Under this circumstance, the apparatus of structuredlight generation 1 can meet the requirement of slimness.

FIG. 4 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a secondembodiment of the present invention. As shown in FIG. 4, the lens unit24 of the apparatus of structured light generation 2 includes a lenselement 16 and a dust-proof plate 18. The lens element 16 of thisembodiment is equivalent to the lens unit 14 of the first embodiment. Incomparison with the first embodiment, the dust-proof plate 18 isadditionally installed in the housing 12 of the apparatus of structuredlight generation 2 of this embodiment. The dust-proof plate is used toprevent external dust or foreign matter from entering the light source10, which is made of glass or non-glass material. Moreover, thearrangement of the dust-proof plate 18 can increase the resistance ofthe light source 18 to the harsh environment and enhance the stabilityof the light source 10. In an embodiment, the dust-proof plate 18 ismade of a BK7 material, the thickness of the dust-proof plate 18 isabout 0.25 mm, and the distance of the dust-proof plate 18 from thelight source 10 is about 0.5 mm. It is noted that the material,thickness and distance of the dust-proof plate 18 are not restricted. Inanother embodiment, the dust-proof plate 18 is made of the same materialas the lens element 16. Moreover, the dust-proof plate 18 is arrangedbetween the light source 10 and the lens element 16. That is, thedust-proof plate 18 is arranged in the range of the first optical pathlength. In the apparatus of structured light generation 2, the lens unit24 constructs a second optical path length for the light beam from thelight source 10. Since the refraction index of the dust-proof plate 18is different from that of air, the second optical path length isdifferent from the first optical path length. The object of the lenselement is not relevant to the imaging purpose of the general opticalimaging device. That is, although the arrangement of the dust-proofplate or any other appropriate medium can generate the different opticalpath length, the lens element of this embodiment is suitably to generatetwo different optical path lengths. After the light beam is convertedinto a linear light beam by the lens element, a structured light isoutputted from the apparatus of structured light generation 2.Consequently, the light beam is effectively shaped. Generally, theoptical path length is the product of a working distance of the lightand the refraction index of the medium. In accordance with the presentinvention, the difference between the working distances of the two ormore optical path lengths is preferably smaller than 1 mm.

FIG. 5 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a third embodimentof the present invention. In this embodiment, the lens unit 34 of theapparatus of structured light generation 3 includes a lens element. Likethe second surface 143′ of the first embodiment as shown in FIG. 2, alenticular lens array structure is formed on the second surface 343 ofthe lens element. Similarly, the lens element of the apparatus ofstructured light generation 3 of this embodiment has a first surface 341facing the light source 10. However, in comparison with the apparatus ofstructured light generation of the first embodiment as shown in FIG. 2,the first surface 341 of the lens element of this embodiment is a flatsurface with a diffracting function. The lens unit 34 is also capable ofgenerating a first optical path length. In this embodiment, the firstsurface 341 with the diffracting function has a phase distribution givenby the following formula:

${\varphi (r)} = {{dor}\frac{2\pi}{\lambda_{0}}\left( {{{df}\; 0} + {{df}\; 1r^{2}} + {{df}\; 2r^{4}} + {{df}\; 3r^{6}} + {{df}\; 4r^{8}} + \cdots} \right)}$

-   where, r²=x²+y².

In the above formula, φ(r) is the phase distribution, r is the distancebetween any point and a center of the first surface 341, and x and y aretwo coordinates of two axes vertical to the optical axis (i.e. the Zaxis). Preferably, the corresponding coefficients include: dor=1, df0=0.0, df1=−6.1691×10̂(−1), df1=2.8442×10̂1, df3=−4.8405×10̂3,df4=2.800×10̂5, df5=4.6892×10̂(−2), and df6=3.1385×10̂(−4).

It is noted that numerous modifications and alterations may be madewhile retaining the teachings of the invention. For example, theprofiles of the first surface and the second surface of the lens elementmay be exchanged. FIG. 6 is a schematic cross-sectional side viewillustrating a variant example of the apparatus of structured lightgeneration according to the third embodiment of the present invention.As shown in FIG. 6, a lenticular lens array structure is formed on thefirst surface 341′ of the lens element that faces the light source 10,and the second surface 343′ of the lens element is a flat surface.

FIG. 7 is a schematic cross-sectional side view illustrating anapparatus of structured light generation according to a fourthembodiment of the present invention. In comparison with the apparatus ofstructured light generation of the third embodiment as shown in FIG. 6,the apparatus of structured light generation 4 of this embodimentfurther includes a dust-proof plate 18. The dust-proof plate 18 isarranged between the light source 10 and the lens element 46 of the lensunit 44. The lens element 46 of the apparatus of structured lightgeneration 4 of this embodiment is equivalent to the lens unit 34 of thethird embodiment. As mentioned above, by the arrangement of the lensunit 44 (or the lens element 46), the apparatus of structured lightgeneration is suitably to generate two different optical path lengths.Moreover, the concepts of the present invention is applied to thesituation where the light source 10 has plural light-emitting chips toresult in different work distances as long as the difference between anytwo working distances is smaller than 1.2 mm.

Please refer to FIGS. 8˜11. FIG. 8 is a schematic perspective viewillustrating an apparatus of structured light generation according to afifth embodiment of the present invention. FIG. 9 is a schematicexploded view illustrating the apparatus of structured light generationaccording to the fifth embodiment of the present invention. FIG. 10 is aschematic exploded view illustrating a variant example of the apparatusof structured light generation according to the fifth embodiment of thepresent invention. FIG. 11 is a schematic exploded view illustratinganother variant example of the apparatus of structured light generationaccording to the fifth embodiment of the present invention. In thisembodiment, the apparatus of structured light generation 5 includes alight source 50, a housing 52 and a lens unit 54. The light source 50includes plural light-emitting chips 501. The plural light-emittingchips 501 are distributed on a circuit substrate 502. The light-emittingchips 501, the circuit substrate 502 and the lens unit 54 areaccommodated within the housing 52. In this embodiment, the lens unit 54is a lens group comprising more than two lens elements. The lens groupincludes a first lens element 541 and a second lens element 542. Thesecond lens element 542 includes plural light-transmissible regions 542a˜542 e. The second lens element 542 may be considered as a mixed typeoptical structure. The light-transmissible regions 542 a˜542 e of thesecond lens element 542 are located in the optical paths of the lightbeams from the light-emitting chips 501. Especially, thelight-transmissible regions 542 a˜542 e are aligned with thecorresponding light-emitting chips 501 in a one-by-one arrangement. Inthis embodiment, the apparatus of structured light generation 5 includesfive light-emitting chips and five light-transmissible regions. Theshapes of the inner surfaces of the light-transmissible regions 542a˜542 e (i.e., the surfaces facing the light source) are independentfrom each other. After the light beams from the light-emitting chips 501pass through the corresponding light-transmissible regions 542 a˜542 eof the second lens element 542, each of the light beams is convertedinto at least one linear light beam by the correspondinglight-transmissible regions 542 a˜542 e. These linear light beams areprojected out to generate a desired structured light pattern accordingto the demand of the designer. Moreover, these linear light beams arelocally overlapped, globally overlapped, or not overlapped. In someembodiments, the light-emitting chips 501 are programmed to beindividually turned on or turned off in the identical or different timesegments.

It is noted that the mixed type optical structure is not restricted tothe second lens element 542 of the lens unit 54. For example, in someother embodiments, the mixed type optical structure contains adiffractive structure, a reflective structure and/or a refractivestructure.

In this embodiment, lenticular lens array structures are formed on theinner surfaces of the corresponding light-transmissible regions 542 a,542 b, 542 c and 542 d, and a lenticular lens array structure along twoorthogonal directions is formed on the inner surface of thelight-transmissible region 542 e. The profiles of the inner surfaces ofthe above light-transmissible regions are presented herein for purposeof illustration and description only. It is noted that the lenticularlens array structures on the inner surfaces of the light-transmissibleregions may be arranged along different directions or have differenttilt angles.

In this embodiment, the housing 52 has a shape of a rectangular sleeve,and the circuit substrate 502 and the first lens element 541 have theshapes of rectangular plates. It is noted that numerous modificationsand alterations may be made while retaining the teachings of theinvention. In the variant example of FIG. 10, the housing 52 and thefirst lens element 541 are integrally formed with each other by aninjection molding process or combined together by any other appropriatemeans. In the variant example of FIG. 11, the housing 52, the first lenselement 541 and the second lens element 542 are integrally formed witheach other by an injection molding process or combined together by anyother appropriate means. As a result, the process of fabricating theapparatus of structured light generation 5 is simplified andtime-saving.

Please refer to FIGS. 12 and 13. FIG. 12 is a schematic perspective viewillustrating an apparatus of structured light generation according to asixth embodiment of the present invention. FIG. 13 is a schematicexploded view illustrating the apparatus of structured light generationaccording to the sixth embodiment of the present invention. Like thefifth embodiment, the apparatus of structured light generation 6 of thesixth embodiment includes a light source 60, a housing 62 and a lensunit 64. The light source 60 includes plural light-emitting chips 601.The plural light-emitting chips 601 are distributed on a circuitsubstrate 602. The light-emitting chips 601, the circuit substrate 602and the lens unit 64 are accommodated within the housing 62. In thisembodiment, the lens unit 64 is a lens group comprising more than twolens elements. The lens group includes a first lens element 641 and asecond lens element 642. The second lens element 642 includes plurallight-transmissible regions 642 a˜642 e. The light-transmissible regions642 a˜642 e of the second lens element 642 are located in the opticalpaths of the light beams from the light-emitting chips 601. Especially,the light-transmissible regions 642 a˜642 e are aligned with thecorresponding light-emitting chips 601 in a one-by-one arrangement. Theshapes of the inner surfaces of the light-transmissible regions 642a˜642 e (i.e., the surfaces facing the light source) are independentfrom each other. In comparison with the fifth embodiment, the housing 62of the sixth embodiment has a shape of a circular sleeve, and thecircuit substrate 602 and the first lens element 641 of the sixthembodiment have the shapes of circular plates.

From the above descriptions, the present invention provides theapparatus of structured light generation. In the apparatus of structuredlight generation, the lens element with the functions of simultaneouslycollimating and shaping the light beam is used as the basic element ofthe lens unit. Consequently, the apparatus of structured lightgeneration can be applied to an optical system with at least two opticalpath lengths in order to generate the infrared structured light. Theoptical path length is composed of one or plural working distances. Theplural working distances may be identical or different as long as thedifference between the working distances is smaller than 1.0 mm. Inother words, the optical system with the apparatus of structured lightgeneration of the present invention is more flexible to be convenientlyoperated by the user. Since the apparatus of structured light generationof the present invention has a compact size, the apparatus of structuredlight generation is suitably installed in the slim type mobile phone.Consequently, regardless of whether the apparatus of structured lightgeneration is installed on a front side or a rear side of the mobilephone, the mobile phone has the function of generating the structuredlight.

While the invention has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the invention needs not be limited to the disclosedembodiments. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. An apparatus of structured light generation,comprising: a light source emitting a light beam; a lens unit convertingthe light beam into a linear light beam; and a housing accommodating thelight source and the lens unit, wherein the housing comprises a firstside and a second side, wherein the first side and the second side areopposed to each other and open to an outside of the casing, a distancebetween the first side and the second side is not larger than 4 mm, thelight source is located near the first side, and the lens unit islocated near the second side, wherein within the housing, the lens unitconstructs a first optical path length and a second optical path lengthfor the light beam, wherein the first optical path length and the secondoptical path length are different.
 2. The apparatus of structured lightgeneration according to claim 1, wherein the lens unit comprises a lenselement, and a radius of a first surface of the lens element is largerthan 0.189 mm, wherein the first surface faces the light source, and thefirst surface is an aspheric surface or has a lenticular lens arraystructure, wherein the first surface has an effective focal lengthsmaller than 1.2 mm.
 3. The apparatus of structured light generationaccording to claim 2, wherein a second surface of the lens element is anaspheric surface or has a lenticular lens array structure, and thesecond surface of the lens unit is close to the second side of thehousing and faces the outside of the housing.
 4. The apparatus ofstructured light generation according to claim 3, wherein the lens unitfurther comprises a dust-proof plate between the light source and thelens element.
 5. The apparatus of structured light generation accordingto claim 1, wherein the lens unit comprises a lens element, wherein afirst surface of the lens element is a flat surface with a diffractingfunction, and the first surface has a phase distribution given by aformula:${\varphi (r)} = {{dor}\frac{2\pi}{\lambda_{0}}\left( {{{df}\; 0} + {{df}\; 1r^{2}} + {{df}\; 2r^{4}} + {{df}\; 3r^{6}} + {{df}\; 4r^{8}} + \cdots} \right)}$where, r²=x²+y², wherein φ(r) is the phase distribution, r is thedistance between any point and a center of the first surface, and x andy are two coordinates of two axes vertical to an optical axis or a Zaxis, wherein dor=1, df0=0.0, df1=−6.1691×10̂(−1), df1=2.8442×10̂1,df3=−4.8405×10̂3, df4=2.800×10̂5, df5=4.6892×10̂(−2), anddf6=3.1385×10̂(−4).
 6. The apparatus of structured light generationaccording to claim 2, wherein the light source comprises plurallight-emitting chips, and the lens element comprises plurallight-transmissible regions, wherein after the light beam from each ofthe light-emitting chips passes through the correspondinglight-transmissible region of the lens element, the light beam isconverted into at least one linear light beam by the correspondinglight-transmissible region, wherein the linear light beams outputtedfrom the plural light-transmissible regions are locally overlapped,globally overlapped, or not overlapped.
 7. The apparatus of structuredlight generation according to claim 6, wherein the plural light-emittingchips are programmed to be individually turned on or turned off inidentical or different time segments.
 8. The apparatus of structuredlight generation according to claim 1, wherein the light sourcecomprises one light-emitting chip, or the light source comprises plurallight-emitting chips that are distributed on a curvy substrate.